Method for the non-releasable connection of components or component regions and non-releasable connection

ABSTRACT

A method for the connection of components or component regions and a non-releasable connection produced in this manner. Two connection faces are partially welded to each other with an adhesive layer being incorporated between the two connection faces. The method including the following steps: arranging a welding base on a connection face, applying the adhesive layer to a connection face, moving the connection faces toward each other in such a manner that the welding base is applied against the other connection face, introducing welding current in the region of the applied welding base. A spacer is arranged between the connection faces before the connection faces are moved toward each other. The connection faces are spaced apart from each other in the region of the welding base by the extent that the welding base projects above the spacer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the U.S. national phase of PCT Application No.PCT/EP2014/063583 filed on Jun. 26, 2014, which claims priority toGerman Application No. DE 102013213109.7 filed on Jul. 4, 2013, thedisclosures of which are incorporated in their entirety by referenceherein.

TECHNICAL FIELD

The present invention relates to a method for the non-releasableconnection of components or component regions and a non-releasableconnection.

BACKGROUND

Welding or bonding connections are used for the non-releasableconnection of at least two components or component regions of anindividual component. The objective is a permanent connection by meansof the materially engaging joining thereof. In welding connections, thebase material is initially partially molten by welding heat. The actualconnection is formed only as a result of subsequent cooling when themolten phase is left. In principle, consequently, all materials whichcan be converted into a molten phase can be welded to each other. Thematerial engagement can be brought about with or without a suitablewelding filler in accordance with the welding method used.

In order to obtain the necessary welding heat, energy must be suppliedfrom the outer side. In addition to the movement energy which isintended to be applied for this purpose during friction welding, thisenergy may also be produced, for example, by means of a suitable heatsource. However, when metal materials are welded, the electricalresistance thereof can be used to obtain local heating directly as aresult of welding current being introduced. Resistance spot welding hasbecome established in particular in the case of thin-walled elementssuch as, for example, bodywork components. Welding is carried outusingwelding tongs engaged around the metal sheets or metal sheet regionsintended to be connected. The metal sheets, are locally pressed againsteach other by electrodes from opposite sides until an electricallyconductive contact is produced between the regions to be welded.Subsequently, the welding current flows via the electrodes through thelocal contact region to form a welded connection.

In addition to the materially engaging connection of component faces bymeans of welding, purely bonding methods are also used in many cases.The bonding layer present between the component faces produces anon-releasable bonding connection.

SUMMARY

In this regard, DE 44 31 991 A1 describes a method for connecting planarcomponents. The components which are intended to be connected maycomprise materials which are identical to or different from each other.In particular, iron-containing and non-iron-containing materials may beinvolved. The actual connection is achieved by the prior application ofan adhesive which hardens under the action of heat. To this end, theadhesive is applied extensively on at least one abutment face of thecomponents to be connected. Subsequently, the components are placed oneach other with the abutment faces thereof. In the first step, only apoint-like bonding connection is brought about between the components.To this end, only part-regions of the abutment faces provided withadhesive are initially heated. In this manner, the adhesive is locallyhardened in order to obtain between the components a connection orfixing which is sufficiently durable at first. Subsequently, thecomponents are supplied to a longer operation of heat in order to hardenthe remaining adhesive up to the final strength of the connection. Inthis manner, preliminary fixing of the components to be connected ispossible as quickly as possible, while the concluding, extensivesolidification is brought about in a subsequent process. Thus, forexample, the concluding heat operation can be carried out in the contextof hardening an applied lacquer in a hardening oven. A correspondinglyefficient use of the necessary time and energy is thereby produced.

On the basis of conventional resistance spot welding, the use of anadditional adhesive layer between the component regions to be connectedis also known. An additional materially engaging connection between thecomponent regions is provided by means of the adhesive layer. Theadvantage of this method which is referred to as adhesive weldinginvolves the production of a highly durable connection. This isparticularly because the connection face which is used for forcetransmission can thereby expand beyond the welding region up to the sizeof the adhesive layer.

The problems known in connection with adhesive welding involve theproduction of the welding connection itself. For instance, the adhesivelayer initially constitutes an initial impediment in order to produce anadequate, electrically conductive contact between the abutting faces ofthe component regions to be connected. This is because inter alia, forexample, the adhesive used in the automotive industry is non-conductive.Consequently, the adhesive layer in the connection region to be weldedtogether has to be either recessed or displaced. Since highly viscousand consequently thick-flowing adhesives are involved in this instance,correspondingly high forces are necessary in order to press thecomponent regions to be connected against each other with the adhesivebeing displaced. Since the pressing forces necessary for this areapplied via electrodes, the electrodes have a correspondingly highdegree of wear. Furthermore, high pressing forces are particularlyunsuitable if they have to be applied from only one side without anadequate counter-bearing.

Ultimately, an inadequate displacement of the adhesive results inundesirable welding defects. Furthermore, many of the adhesives used canbe locally displaced only using an additional auxiliary connectioncircuit. This is used for the temporary preheating of the adhesive inorder to reduce the viscosity thereof. However, the process reliabilityof the adhesive welding is reduced by the use of an additional auxiliaryconnection circuit. The adhesive gap produced in this manner isnon-uniform as a result of the changes typical in adhesive weldingbetween regions which are bonded and welded to each other. Furthermore,the adhesive gap does not have in the welding regions any more spacingbetween the component regions connected to each other. Consequently, thethickness of the adhesive layer varies over the connection face.Consequently, the adhesive gap cannot generally be adjusted.

In order to achieve adjustability of the adhesive gap, the projectionwelding method is further known. In this instance, the contact necessaryfor welding between the component faces to be connected is produced bymeans of so-called welding projections. A welding projection is usuallya deformation which is pressed into at least one thin-walled component.While an indentation is thereby produced at one side of the component,the opposite side has the necessary protrusion in the form of aprojection. The component faces fabricated in this manner are alsowelded by means of electrodes. These electrodes may be a component ofwelding tongs, as also used in conventional resistance spot welding oradhesive welding.

As a result of the contact face size which is predetermined by means ofthe welding projection, the electrical current density which can thus beachieved is not dependent on the size of the electrodes. In other words,electrodes which taper so as to be thin and which consequently wearquickly must not be used in this instance in order to obtain a limitedcontact region. Consequently, it is possible in the projection weldingmethod to use planar electrodes which have correspondingly lesselectrode wear. In this context, there are known methods which combinethe said projection welding method with the use of an adhesive layer.

In this regard, DE 33 26 612 A1 describes a method for connecting twometal plates by means of a resistance spot weld. Before the actualwelding, a projection-like deformation is first pressed into a firstplate. The projection is provided in order to produce the electricallyconductive contact necessary for welding with respect to a second plate.In order to improve the connection to be produced, at least one of thetwo plates is provided with an adhesive layer in the deformation region.The adhesive layer is applied at the side of the plate that has aprotrusion in the deformation region. Subsequently, the first platehaving the protrusion thereof is placed against an abutment region ofthe second plate and pressed into the adhesive layer and the secondplate. By electrodes being applied in the deformation region, a weldingcurrent which flows from one plate through the protrusion into the otherplate is finally applied to the plates. As a result, the metal of theplates is locally molten in the deformation region, whereby a materiallyengaging connection is produced. Consequently, the material engagementcomprises the welding connection and the adhesive connection.

The combination of the projection welding method with the arrangement ofan adhesive layer already affords many advantages. As a result of thepresent formation of the welding projection, the adhesive layer can bedisplaced locally substantially more easily because the pressing forcewhich can be introduced via the electrodes is distributed over asurface-area which is only small. The high compressive strain which canbe achieved in this manner under the welding projection again results inthe necessary pressing force generally being able to be reduced. Animproved electrically conductive contact can be achieved as a result ofthe simple local displaceability of the adhesive layer. Furthermore, thearrangement of an auxiliary connection circuit which is sometimesnecessary is dispensed with so that the process reliability is generallyincreased.

Nevertheless, the extent of the adhesive gap also cannot be adjusted inthis instance. Thus, the melting process during the welding operationfirst starts at the tip of the weld projection and initiates the growthof a weld nugget. In this instance, the welding projection is completelyconverted into the molten phase. As a result, the initial protrusion ofthe welding projection is compressed after the welding and isconsequently no longer available. Furthermore, the component faces whichare connected to each other are also thereby located flat on each other.

Consequently, the known welding methods and the welding connectionswhich can be produced therewith certainly still leave room forimprovement.

Against this background, an object of the present invention is toimprove a method for the non-releasable connection of components orcomponent regions so that a combined connection of welding and bondingcan be achieved in a process-reliable manner, wherein the necessaryadhesive gap can be adjusted. Furthermore, there is intended to be setout an improved non-releasable connection which comprises a combinationof welding and bonding, wherein the necessary adhesive gap is alsoformed in the region of the welding.

The solution to the method-related portion of this object is set out inthe method having the features of claim 1. The device-related portion ofthis object is solved by the features of claim 6. Additional,particularly advantageous embodiments of the invention are disclosed inthe dependent claims.

It should be noted that the features set out individually in thefollowing description can be combined with each other in any technicallyadvantageous manner and set out additional embodiments of the invention.The description further characterizes and specifies the invention inparticular with reference to the Figures.

As a result of the method according to the invention for thenon-releasable connection of components or component regions, twoconnection faces are at least partially welded to each other with anadhesive layer being incorporated. In this regard, the following stepsare envisaged:

arranging a welding base on a connection face,

applying the adhesive layer to a connection face,

moving the connection faces toward each other, wherein the welding baseis applied against the other connection face and

introducing welding current in the region of the applied welding base.

It should be mentioned that the arrangement of the at least one weldingbase can be carried out both before and after the adhesive layer isapplied. Accordingly, the application of the adhesive layer can becarried out before or after the at least one welding base has beenarranged. Naturally, it is also conceivable to carry this out in aparallel manner by simultaneously arranging the welding base andapplying the adhesive layer. Preferably, the application of the adhesivelayer is carried out only after the at least one welding base has beenarranged on one of the connection faces.

In relation to the envisaged construction of the connection, the weldingbase and adhesive layer can be arranged and applied together on one andthe same connection face. However, the at least one welding base may bearranged on a first connection face while the adhesive layer is appliedto a second connection face and consequently to the respective otherconnection face. The adhesive layer and welding base are preferablyarranged on different connection faces. The approach movement of the twoconnection faces prefabricated in this manner is thereby carried out insuch a manner that the welding base is applied against the otherconnection face with the adhesive layer being displaced locally,respectively. The abutment of the welding base against the oppositeconnection face serves to produce an electrically conductive contact inorder even to be able to carry out the resistance welding used with theintroduction of welding current.

According to the invention, before the connection faces which areintended to be connected to each other in a non-releasable manner aremoved toward each other, a spacer is arranged therebetween. In thisinstance, it should be noted that the welding base projects above thespacer. In other words, the extent of the spacer extending between themutually approached connection faces should be selected in such a mannerthat a spacing remains between the spacer and at least one connectionface when the welding base is already in the applied state.

In this instance, the particular advantage involves the additionalarrangement of the spacer. The remaining spacing between the connectionfaces which are positioned on each other and which are pressed againsteach other during the welding operation in the region of the weldingbase can thereby be controlled. In known manner, the melting process ofthe welding base also starts here initially at the tip thereof, whichmelting process begins by the welding current being introduced. Duringthe growth of a weld nugget initiated in this manner, the weldingprojection is also completely converted into the molten phase in thisinstance. However, it is now no longer possible to completely press thewelding projection together as a result of the spacer according to theinvention. Consequently, it is still possible for the connection facesto be moved toward each other only up to the time at which the spacerblocks further compression. As a result, it can consequently no longerbe the case that the connection faces are located flat on each other.The spacer itself is not melted.

As a result of the readily achievable application of the weldingprojection against the other connection face, respectively, a sufficientelectrically conductive contact is produced. In this instance,consequently, it is not necessary to arrange an auxiliary connectioncircuit, whereby the required process reliability is provided.Furthermore, the remaining adhesive gap between the connection faces isno longer produced in an uncontrolled manner. To this end, the initiallyproduced spacing between the spacer and the connection face orconnection faces should be defined by the configuration of the spacer.In this manner, the adhesive gap remaining during the connection processand in particular during the welding operation between the connectionfaces can be adjusted. The variable necessary for adjusting the adhesivegap is consequently the dimension by which the welding base projectsabove the spacer or the spacer falls below the height of the weldingbase. That dimension stands for the difference by which the connectionfaces can be further moved toward each other during the weldingoperation in the region of the welding base.

The arrangement of the welding base allows large electrodes to be used.Depending on requirements, there can also be used in this instanceelectrodes which are suitable as a result of their planar extent forwelding two or more welding bases in a single operation. The method setout is also suitable for welding with electrodes applied at one side asa result of the pressing forces, which are only small, necessary for theapplication of the welding projection. Particularly during simultaneouswelding of two or more welding bases, the necessary short-circuit of thewelding current across the welding base can be brought about. The use oflarge, in particular flat, electrodes results in the advantageous sideeffect that the adhesive layer can be compressed in the adhesive gapbetween a plurality of welding bases during the welding process via theelectrodes. A non-releasable connection which is process-reliable to agreat extent is thereby produced. The use of large electrodes furtherbrings about electrode wear which is only slight. Particularly inconnection with high welding currents such as, for example, when weldingcomponents or component faces of aluminum, a long service-life thereofis produced when large electrodes are used as a result of the reducedwear.

By a suitable spacer being selected, the adhesive gap can now beselectively adjusted and in particular adapted to the requirements ofthe adhesive used.

The material used for the spacer may be a material which is electricallyconductive or which is not electrically conductive. Preferably, thespacer is formed by an electrically conductive material or has at leastone electrically conductive material. At the beginning of the weldingprocess, the spacer does not have any physical contact with at least oneof the connection faces. Consequently, the spacer is also not convertedinto a molten phase as a result of the electrically conductive contactwhich is consequently not present at the beginning of the weldingprocess. A controlled stop of further approach movement of theconnection faces is provided as a result of the solidity of the spacer,which solidity is consequently also present during the weldingoperation.

Furthermore, the welding operation can be simultaneously stopped whenfurther approach movement of the connection faces is stopped. The causeof this is the instantaneous increase occurring at this time of theelectrically conductive surface-area which is produced when the spacercontacts the connection faces. That surface-area comprises at that timeat least a portion of the spacer and the welding base. As a result ofthe immediate increase in surface-area, the current density of theintroduced welding current abruptly decreases so that the weldingprocess is instantaneously interrupted.

In the context of the invention, it is conceivable for the welding baseand/or the spacer to be present in the form of elements which areinitially independent of the connection faces. Thus, for example, thewelding base may be arranged on one of the connection faces via anadhesive, screw type, insertion type or welding connection in amaterially engaging, positive-locking and/or non-positive-lockingmanner. In the case of an adhesive connection, the welding base may bearranged, for example, on one of the connection faces in the context ofthe application of the adhesive layer over that layer. Theabove-mentioned connection types apply accordingly to the arrangement ofthe spacer.

In an advantageous embodiment of the method according to the invention,there is provision for the welding base to be pressed as a protrusionout of the associated connection face. Alternatively or additionally,the spacer may also be pressed as a protrusion out of the associatedconnection face. The welding base and/or the spacer may thereby be amaterially uniformly integral component of the components or componentfaces which are intended to be connected to each other.

The resultant advantage involves the extremely simple production of thewelding base and/or the spacer. In particular thin-walled components orcomponent faces have easy deformability in the present sense. Thus, thewelding base and/or the spacer can advantageously be formed by a rearside of the component or component face as a bulge or protrusion whichis directed therein, which rear side faces away from one of theconnection faces, respectively. As a result, the part-region of thecomponent or the component face displaced in this manner is positionedbeyond the connection face as a welding base and/or as a spacer.Depending on the thickness of the material used in that part-region,extremely precise embodiments of the welding base and/or spacer can thusbe produced.

As already set out above in connection with the arrangement of thewelding base, the spacer can naturally also be applied to one of theconnection faces together with the adhesive layer. In this instance, itwould be conceivable to integrate the spacer in the mass of theadhesive, which mass is shapeless per se, which spacer is then arrangedon the corresponding connection face at the same time as the applicationof the adhesive layer. However, the spacer may also be selectivelyarranged only after the adhesive layer has been applied. In thisinstance, the spacer remains at the necessary region of the connectionface as a result of the adhesive properties of the adhesive layer.

In this manner, the spacer can be formed from a material which isdifferent from the component or component region. In this instance,non-conductive materials would be conceivable, but also ones which areconstructed, for example, in a resilient manner. In order neverthelessto obtain the necessary stop during the approach movement of theconnection faces by means of the spacer constructed in this manner, theflexibility thereof can be adjusted, for example, progressively. Theresistance thereof with respect to the resilient behavior thereof wouldthereby increase with increasing deformation until the approach movementis stopped. It would also be further conceivable to use an adhesivewhich is initially solid but which can be melted as a spacer. In thismanner, an initial stop of the approach movement in question may bebrought about during the welding process, wherein the spacer constructedin this manner can melt during a subsequent thermal processingoperation. This is particularly advantageous when the adhesive layerused is hardened by such a thermal processing operation.

With regard to the position of the spacer and welding base relative toeach other, a step of the invention makes provision for them to be ableto be arranged with spacing from each other. It would thereby bepossible substantially to ensure that the welding base which isconverted into the molten phase does not have any influence on thespacer during the welding process. Thus, it is thereby possible toselectively prevent the spacer from also being converted at leastpartially into a molten phase during the welding process or at leastfrom being weakened. Furthermore, as a result of the arrangement withspacing from each other, regions, which could otherwise undergo anexcessively large approach movement of the connection faces, can beselectively supported between the connection faces by the spacer. Suchembodiments may be necessary, for example, in spatially formedcomponents or component faces in order to achieve a controlled endposition of the connection regions relative to each other. Asubstantially uniform adhesive gap is thereby advantageously formed.

As a preferred alternative embodiment, the spacer and the welding basemay naturally also be arranged together as a unit on one of theconnection faces. The term “unit” in the context of the invention isintended to mean that the respective shapes and/or contours thereofmerge into each other. In this instance, the particular advantageinvolves the simple common arrangement of the welding base and spacer ina single operation. Particularly when the welding base and spacer arepressed out of one of the connection faces, they can be producedtogether with a single shaping tool, in particular with a correspondingpunching stamp. As a result of the immediate proximity of the spacer andwelding base, a selective stop of the approach movement is furtherproduced in an advantageous manner precisely at a location where anintroduction of force occurs during the welding process. Aprocess-reliable and precise formation of the adhesive gap which isintended to be adjusted by means of the spacer is thereby possible.

Depending on requirements and the embodiment of the components orcomponent faces to be connected, a combination of the positionalpossibilities set out above in respect of the welding base and spacerrelative to each other may also be advantageous. In this instance, thewelding base and spacer would be arranged in some regions as a unit,while in other regions there would be a spacing of the welding base andspacer.

The above-explained method for the non-releasable connection ofcomponents or component regions is an extremely advantageous possibilityfor achieving precise adjustability of the adhesive gap in addition to aprocess-reliable connection. The arrangement of the spacer ensures thatthe otherwise inaccessible adhesive gap between the connection faces hasprecisely the extent which allows a maximum in terms of solidity for theplanar adhesion by means of the adhesive layer. Therefore, pressing theconnection faces against each other in a flat manner in the region ofthe welding base is a thing of the past. As a result of thesubstantially uniform configuration of the resultant adhesive gap, therisk that the connection may not be sufficiently durable in a constantmanner as a result of an excessively small thickness or a non-existentthickness of the adhesive layer is eliminated.

The invention further provides for a non-releasable connection which isproduced by the above-described method between two components orcomponent regions. In this instance, two connection faces are welded toeach other by resistance welding with an adhesive layer beingincorporated via a welding base which is arranged on a connection face.A spacer is arranged between the connection faces according to theinvention. In this instance, a significant aspect is the fact that theconnection faces are spaced apart from each other in the region of thewelding base. In other words, the connection faces also have betweenthem, in the region of the welded welding base, an adhesive gap whichsubstantially corresponds to the remaining adhesive gap in terms of thethickness thereof.

The resultant advantages have already been explained in the context ofthe method set out so that reference may be made at this point to thecorresponding explanations within the present description. Furthermore,this also applies to the subsequent explanations in relation to thedevice-related portion of the invention.

In an advantageous development, there is provision for the welding baseand/or the spacer to be pressed as a protrusion(s) out of the associatedconnection face. Naturally, the spacer and/or the welding base may alsobe an additional element which is not a materially uniformly integralcomponent of the components or component faces which are intended to beconnected. In this regard, in particular the spacer may be arranged as aseparate element on one of the connection faces.

In the context of the invention, it is further envisaged that the spacercan be arranged with spacing from the welding base. In an alternativeembodiment, the spacer and the welding base may be constructed as aunit.

The above-described method according to the invention for thenon-releasable connection of components or component regions and thenon-releasable connection according to the invention are not limited tothe measures and embodiments disclosed herein but naturally also includeadditional measures and embodiments which have the same effect.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-section of a method known in the prior artfor resistance spot welding in the form of adhesive welding shortlybefore the introduction of the necessary welding current;

FIG. 2 shows in the same manner the resistance spot welding known in theprior art from FIG. 1 after the welding process has ended;

FIG. 3 shows in the same manner the result of the resistance spotwelding known in the prior art from FIG. 2 shortly before carrying outadditional resistance spot welding;

FIG. 4 shows in the same manner the result of the two resistance spotweldings known in the prior art from FIG. 3 after the welding processhas ended;

FIG. 5 is a schematic cross-section of a conventional projection weldingmethod known in the prior art shortly before the introduction of thenecessary welding current;

FIG. 6 shows in the same manner the result of the projection weldingmethod known in the prior art from FIG. 5 after the welding process hasended;

FIG. 7 is a schematic cross-section of a method known in the prior artfor projection welding in the form of adhesive welding shortly beforethe components to be connected are moved together;

FIG. 8 is a cross-section of the method known in the prior art foradhesive welding from FIG. 7 shortly before the introduction of thenecessary welding current, and

FIG. 9 shows in the same manner the result of the method known in theprior art for adhesive welding from FIGS. 7 and 8 after the weldingprocess has ended.

Additional advantageous details and effects of this disclosure areexplained in greater detail below with reference to embodiments whichare illustrated in the following Figures, in which:

FIG. 10 is a schematic plan view of a welding base in combination with aspacer according to the invention;

FIG. 11 is a cross-section of the combination of the welding base andspacer from FIG. 10;

FIG. 12 is a schematic cross-section of a method for connectingcomponents or component faces using the combination from FIGS. 10 and 11during the approach movement;

FIG. 13 shows in the same manner the result of the method from FIGS. 10to 12 after the welding process has ended;

FIG. 14 is a schematic plan view of an alternative combination withrespect to FIG. 10 comprising the welding base and the spacer;

FIG. 15 is a cross-section of the alternative combination of a weldingbase and spacer from FIG. 14;

FIG. 16 is a schematic cross-section of a method for connectingcomponents or component faces using the combination from FIGS. 14 and 15during the approach movement;

FIG. 17 shows in the same manner the result of the method from FIGS. 14to 16 after the welding process has ended;

FIG. 18 shows in the same manner the result of the method from FIGS. 10to 13 using a large electrode after the welding process has ended, and

FIG. 19 is a plan view of a selection of schematically illustratedcombinations of the welding base and spacer.

DETAILED DESCRIPTION

As required, detailed embodiments of the present invention are disclosedherein; however, it is to be understood that the disclosed embodimentsare merely exemplary of the invention that may be embodied in variousand alternative forms. The figures are not necessarily to scale; somefeatures may be exaggerated or minimized to show details of particularcomponents. Therefore, specific structural and functional detailsdisclosed herein are not to be interpreted as limiting, but merely as arepresentative basis for teaching one skilled in the art to variouslyemploy the present invention.

The following descriptions in relation to FIGS. 1 to 9 relate to weldingmethods which are known from the prior art. The associated explanationsserve to set out the associated disadvantages with regard to theconnection of two components. It is thereby intended to provide a betterunderstanding of the method according to the invention and thenon-releasable connection according to the invention which can beproduced in this manner.

FIG. 1 first shows the prior art for a known method for resistance spotwelding in the form of adhesive welding. In this instance, a firstcomponent 1 and a second component 2 are intended to be welded to eachother partially with an adhesive layer 3 being incorporated.

The adhesive layer 3 has previously been applied in a manner notillustrated in greater detail at least to a first connection face 4 ofthe first component 1 or to a second connection face 5 of the secondcomponent 2. Naturally, the adhesive layer 3 can also be applied to bothconnection faces 4, 5. Subsequently, the two components 1, 2 werepositioned one on the other, as can be seen in FIG. 1 as a result. Whilethe two connection faces 4, 5 were moved toward each other in a mannernot illustrated, a planar contact of the adhesive layer 3 with respectthereto was able to be produced.

In order now to obtain a local welding location, a first electrode 7 isapplied to a first rear side 6 of the first component 1 facing away fromthe first connection face 4 and a second electrode 9 is applied to asecond rear side 8 of the first component 1 facing away from the secondconnection face 5. In this instance, the two electrodes 7, 9 aredirectly opposite each other. The electrodes 7, 9 are provided toconduct a welding current through the two components 1, 2. To this end,the two components 1, 2 are produced from an electrically conductivematerial. In order to be able to introduce the welding current via theelectrodes 7, 9, the electrodes are connected to a circuit 10. For thispurpose, the two electrodes 7, 9 are connected to a current source 12via physical lines 11.

The actual welding operation is carried out via a short-circuit (notillustrated here) of the circuit 10. In this instance, the circuit 10 isopened, as illustrated by the indication of the lines 11 between the twoelectrodes 7, 9. The short-circuit and consequently the closure of thecircuit 10 is brought about by the two connection faces 4, 5 being movedtogether as illustrated in FIG. 2 by means of the local compressionthereof by means of the electrodes 7, 9 which move toward each other.This movement is carried out until the connection faces 4, 5 arepartially located on each other and thus have a local, electricallyconductive contact therebetween. High electrode forces F are necessaryin order to displace the adhesive layer 3 in the region between the twoelectrodes 7, 9.

FIG. 2 shows the short-circuited state in which the welding currentflows from one of the electrodes 7, 9 through the touching connectionfaces 4, 5 of the two components 1, 2 into one of the other electrodes7, 9. There is thereby produced local heating, by means of which thetouching connection faces 4, 5 are partially melted. After the weldingcurrent is switched off, the molten and subsequently cooling regions areconverted into a materially uniform, materially engaging connection. Alocal welding connection 13 has thereby been produced between the twocomponents 1, 2. As may be seen, the adhesive layer 3 has been almostcompletely displaced in the region of the welding connection 13. A typeof crater is produced as a result of the resultant deformation of thecomponents 1, 2 with respect to the adhesive layer 3 which remains in asurrounding manner so that the adhesive layer 3 tapers in a wedge-likemanner toward the welding connection 13 in terms of the extent thereof.

FIG. 3 illustrates the components 1, 2 which are connected to each otherby means of the welding connection 13 and the adhesive layer 3. Withinthe welding connection 13, a weld nugget 14 which is formed during thewelding process is indicated as an oval. In this instance, an additionalwelding connection 13 is intended to be produced in the manner describedabove with spacing from the welding connection 13. Reference may be madeto the explanations relating to FIGS. 1 and 2 with regard to theindividual steps necessary for this.

FIG. 4 shows the result of two welding connections 13 which are spacedapart from each other. As a result of the above-described problemsresulting from the displacement of the adhesive layer 3, this is nowformed in a lozenge-like manner between the two welding connections 13.As a result, an adhesive gap 15 filled with the adhesive layer 3 in anextremely non-uniform manner in relation to the extent of the twoconnection faces 4, 5 relative to each other.

FIG. 5 now shows an arrangement with which a projection welding methodcan be carried out. Unlike the conventional resistance welding set outabove, this is distinguished by the arrangement of a welding base 16. Inthis case, the welding base 16 may also be referred to as the weldingprojection. As can be seen, the welding base 16 is formed in thisinstance from the first component 1. To this end, the component 1 waspartially positioned from the first rear side 6 thereof toward the firstconnection face 4 thereof. The welding base 16 allows simple,electrically conductive contact which is produced quasi per se via a tip17 of the welding base 16. Consequently, the two components 1, 2 onlyhave to be pressed against each other with substantially less electrodeforce F during the welding process. In this regard, substantially largerelectrodes 7, 9 can also be used in comparison with conventionalresistance welding because it is not necessary to introduce theelectrode force F in a point-like manner.

FIG. 6 sets out the result of the welding process. By the weldingcurrent being introduced, the welding base 16 was converted into amolten phase in which the weld nugget 14 was formed. In this instance,however, the two components 1, 2 were moved together by means of theelectrode force F to such an extent that they are now located one on theother with the connection faces 4, 5 thereof. The cause of this is themelting of the welding base 16 which was completely compressed.

The combination of the projection welding method shown in FIGS. 5 and 6with adhesive welding is now illustrated in FIG. 7. As can be seen, inaddition to the arrangement of the welding base 16 on the firstcomponent 1, the adhesive layer 3 is now also applied to the secondconnection face 5 of the second component 2 for this purpose. The stateshown constitutes the intact adhesive layer 3, wherein the twocomponents 1, 2 are still spaced so far apart from each other that thetip 17 of the welding base 16 has not yet been introduced into theadhesive layer 3.

FIG. 8 illustrates the first step of the approach movement of the twoconnection faces 4, 5 by means of the electrode force F. In thisinstance, the welding base 16 is urged with local displacement of theadhesive layer 3 through the layer until the tip 17 of the welding base16 is applied against the second connection face 5 of the secondcomponent 2. From this time on, an electrically conductive contact isproduced and the two connection faces 4, 5 are in planar contact withthe adhesive layer 3. After the welding current has been introduced viathe circuit 10, the conversion of the welding base 16 into a moltenphase now begins in the manner already described. At the same time, thetwo connection faces 4, 5 are locally moved toward each other by meansof the electrode force F in the region of the welding base 16.

The result of the welding process as illustrated in FIG. 9 shows thatthe two components 1, 2 are deformed in a crater-like manner similarlyto in conventional resistance welding in the form of adhesive welding.Although a residual quantity of the adhesive layer 3 as far as the weldnugget 14 formed is sometimes still present, it is also displaced inthis instance in a wedge-like manner toward the welding connection 13produced.

Against this background, it is clear that the adhesive welding which isadvantageous per se generally has disadvantages in terms of aselectively adjustable adhesive gap 15 being obtained. In particular asa result of the variable extents of the adhesive layer 3, there may beproduced in this instance regions which do not have a sufficientlydurable connection by means of the adhesive layer 3. The followingdescription regarding FIGS. 10 to 19 serves to explain the present.

FIG. 10 is a plan view of an embodiment according to the invention inthe region of the welding connection to be produced as a cut-out usingthe example of the component 1. By viewing the first connection face 4,it is possible to see the arrangement of the welding base 16 as alreadyknown in the prior art. In this instance, the arrangement has anelongate configuration which extends in a bar-like manner over a partialregion of the connection face 4. According to the invention, a spacer 18is further arranged on the connection face 4. In this instance, thespacer 18 also has an elongate configuration which extends in a bar-likemanner over a partial region of the connection face 4. In this instance,the welding base 16 and spacer 18 are orientated relative to each otherso that they intersect with each other. In this case, the welding base16 and spacer 18 together form an angle w which is 90° in this instance.As already indicated here, the welding base 16 projects above the spacer18, which is again better illustrated in FIG. 11.

FIG. 11 illustrates the arrangement according to the invention of thewelding base 16 and spacer 18 from FIG. 10 as a longitudinal section ofthe first component 1 through the spacer 18. As already mentioned, thewelding base 16 projects above the spacer 18. In this instance, the tip17 of the welding base 16 directed downward in FIG. 11 is spaced apartfrom the first connection face 4 at a spacing x1. However, an upperregion 19 of the spacer 18 is spaced apart from the first connectionface 4 at a spacing x2. As can be seen, the spacing x1 of the tip 17from the first connection face 4 is greater than the spacing x2 of theupper region 19 from the first connection face 4. The term “projectingabove” is intended in accordance with the invention to mean preciselythat relationship of the two above-mentioned spacings x1, x2.

FIG. 12 again shows, from FIG. 11, the first component 1 which isprefabricated according to the invention and which is now intended to beconnected to the second component 2 with the adhesive layer 3 beingincorporated. The illustration substantially corresponds to the statealready shown in FIG. 8, according to which the tip 17 of the weldingbase 16 abuts a partial region of the second connection face 5 of thesecond component 2 with local displacement of the adhesive layer 3.Subsequently, the welding current is introduced in a manner not shownvia the circuit 10 and in particular via the two electrodes 7, 9. Asalready described in the previous contexts, the welding base 16 isconverted in this case into a molten phase beginning at the tip 17thereof. At the same time, the electrodes are moved toward each other ina manner not shown by means of the electrode force F so that the twoconnection faces 4, 5 are moved nearer each other. The approach movementis carried out until the first component 1 abuts a partial region of thesecond connection face 5 of the second component 2 by means of thespacer 18, as can be seen in FIG. 13.

FIG. 13 shows the result of the method according to the invention,according to which the welding connection 13 was produced with the weldnugget 14 being formed in addition to the adhesive connection by meansof the adhesive layer 3. The uniform formation of the welding gapbetween the connection faces 4, 5 can clearly be seen. The adhesivelayer 3 thereby has a substantially uniform extent. In this instance,the adhesive layer 3 extends as far as the welding connection 13 withouta wedge-like tapering having been formed by local deformation of one ofthe components 1, 2.

FIG. 14 shows an alternative embodiment or arrangement of the weldingbase 16 and spacer 18 relative to each other as a plan view of the firstconnection face 4 of the first component 1. Unlike the configuration ofFIG. 10, they are not arranged in this instance at an angle w butinstead extend parallel with each other. In the parallel arrangementthereof, the welding base 16 and spacer 18 are spaced apart from eachother. In this instance, the welding base 16 and spacer 18 are alsoconstructed in a bar-like manner. With regard to the illustration ofFIG. 14, the welding base 16 is arranged in this instance on the rightwhile the spacer 18 is located to the left of the welding base 16.

FIG. 15 shows the alternative arrangement of the welding base 16 andspacer 18 of FIG. 14 as a section through it and the first component 1.As can be seen, the welding base 16 also projects above the spacer 18 inthis instance. As already set out in relation to FIG. 11, the upperregion 19 of the spacer 18 is also spaced apart here from the firstconnection face 4 of the first component 1 at a spacing x2 which issmaller than the spacing x1 of the tip 17 of the welding base 16 fromthe first connection face 4.

FIG. 16 shows the state of the welding base 16 which is applied with thetip 17 thereof to a partial region of the second connection face 5 ofthe second component 2. This state corresponds to an extremely greatextent to the illustration in FIG. 12, only with the alternativearrangement of the welding base 16 and spacer 18. In this instance, itis also possible to clearly see that the electrically conductive contactnecessary for the subsequent welding process is provided only by meansof the tip 17 of the welding base 16 while the spacer 18 is initiallyspaced apart with the upper region 19 thereof from the second connectionface 5.

FIG. 17 shows the result of the welding process which substantiallycorresponds to the result in FIG. 13. The approach movement of the twoconnection faces 4, 5 was also stopped in this instance by thearrangement of the spacer 18, wherein the welding connection 13 isformed in the region of the welding base 16. As can be seen, theremaining residual quantity of welding base 16 can be adjusted by meansof the difference between the two spacings x1, x2 thereof with respectto the first connection face 4. Thus, a specific portion of the weldingbase 16 is left in this instance so as to form the weld nugget 14.However, the welding base 16 in FIG. 13 is almost completely compressed.

FIG. 18 shows a larger arrangement of two components 1, 2 which areconnected to each other and which have been welded by means of a totalof four welding connections 13 in this instance. In this instance, thewelding process is illustrated at a time at which the two connectionfaces 4, 5 have already been moved toward each other, the approachmovement has been stopped and the weld nuggets 14 are formed. Thisschematic illustration is intended to illustrate the advantage of themethod according to the invention in conjunction with a large firstelectrode 7, in particular with the electrode force F being introducedat one side.

As can be seen, the second electrode 9 is reduced in this instance to asmall partial region between two welding connections 13, wherein ittakes up only a contact closure and not the function of acounter-bearing with respect to the electrode force F of the firstelectrode 7. For this purpose, the two components 1, 2 are supported atthe end regions thereof by means of suitable bearings 20 which applynecessary reaction forces F/2 to the electrode force F in order toproduce a static equilibrium. As a result of the first electrode 7 whichspans at least two welding connections 13, those connections were ableto be produced within a single operation by the welding current beingable to flow between the electrodes 7, 9 via the circuit 10. As a resultof the extent of the first electrode 7, it was further also possible tocompress a number of partial regions of the adhesive layer 3 between thewelding connections 13 in an advantageous manner. An extremely preciseadhesive gap 15 was thereby able to be formed between the connectionfaces 4, 5.

FIG. 19 shows various alternative embodiments of the arrangementaccording to the invention of the welding base 16 and spacer 18 as aschematic plan view. In this instance, a total of four constructionvariants are shown at the same time. The arrangement possibilities arenot reduced to those shown here but instead also comprise otheradvantageous forms which are consequently equivalent.

With reference to the illustration of FIG. 19, there is shown on thevery left a variant which has already been described in connection withFIGS. 10 to 13. In this instance, the welding base 16 and spacer 18intersect, wherein they together define the angle w. That angle is also90° in this instance, as already shown in FIG. 10.

There is shown on the right beside the intersecting embodiment a variantin which the welding base 16 has been constructed as a bar as above.However, the spacer 18 has a point-like configuration. The diameter ofthe spacer 18 substantially corresponds in this instance to thecross-sectional width of the bar-like welding base 16. In thisembodiment, a total of two spacers 18 are further combined with awelding base 16. In this instance, the point-like spacers 18 arearranged beside the longitudinal sides of the bar-like welding base 16with spacing therefrom. The position thereof is a mirror-image inrelation to the longitudinal direction of the bar-like welding base 16.

Furthermore, on the right beside the above-described embodiment, theparallel arrangement of the welding base 16 and spacer 18 appears again,as already shown in FIGS. 14 to 17.

On the very right in FIG. 19, there is illustrated an embodiment whichcomprises two welding bases 16 and two spacers 18. They are arrangedaround a notional center and curved around that center in a planarmanner. In this manner, the spacers 18 and welding bases 16 togetherform a circular arrangement which is interrupted at the changes betweenthe spacers 18 and welding bases 16. The spacers 18 and welding bases 16alternate with each other in the peripheral direction of that circulararrangement.

LIST OF REFERENCE NUMERALS

-   1 First component-   2 Second component-   3 Adhesive layer between 1 and 2-   4 First connection face of 1-   5 Second connection face of 2-   6 First rear side of 1-   7 First electrode-   8 Second rear side of 2-   9 Second electrode-   10 Circuit-   11 Line of 10-   12 Current source of 10-   13 Welding connection between 1 and 2-   14 Weld nugget of 13-   15 Adhesive gap between 4 and 5-   16 Welding base-   17 Tip of 16-   18 Spacer-   19 Upper region of 18-   20 Bearing-   F Electrode force-   F/2 Reaction force-   w Angle between 16 and 18-   x1 Spacing between 17 and 4-   x2 Spacing between 19 and 4

While exemplary embodiments are described above, it is not intended thatthese embodiments describe all possible forms of the invention. Rather,the words used in the specification are words of description rather thanlimitation, and it is understood that various changes may be madewithout departing from the spirit and scope of the invention.Additionally, the features of various implementing embodiments may becombined to form further embodiments of the invention.

The invention claimed is:
 1. A method for non-releasably connectingcomponents or component regions, wherein two connection faces arepartially welded to each other and are bonded with an adhesive layer,the method comprising: forming a welding base on one of the connectionfaces; forming a spacer on one of the connection faces at a locationspaced from the welding base, wherein the welding base projects abovethe spacer, and wherein the steps of forming the welding base and thespacer are performed by pressing protrusions out of the associatedconnection face; applying the adhesive layer on one of the connectionfaces, moving the connection faces toward each other to press thewelding base against the connection face that does not include thewelding base, and supplying welding current through the welding base tomelt the welding base until the spacer stops the connection faces frommoving toward each other.
 2. The method as claimed in claim 1, whereinthe spacer is applied to one of the connection faces together with theadhesive layer.
 3. A method of welding two components togethercomprising: providing a welding base on one component; providing aspacer on one component spaced from the welding base, wherein thewelding base projects above the spacer, and wherein the steps ofproviding the welding base and the spacer are performed by pressingprotrusions out of the associated connection face; applying an adhesivebetween the two components; connecting the two components through thewelding base; and supplying welding current through the components andthe welding base to melt the welding base until the spacer is in contactwith both components.
 4. The method of claim 3, wherein a gap is definedbetween the spacer and one of the components, and wherein melting thewelding base reduces the thickness of the welding base until the spacercloses the gap and comes into contact with both of the components. 5.The method of claim 4, wherein when the spacer comes into contact withboth of the components an adhesive gap is defined between the twocomponents by the spacer.
 6. The method of claim 4, wherein the step ofsupplying welding current is interrupted when the spacer closes the gapby coming into contact with both of the components.
 7. The method ofclaim 3 wherein the welding base has a first thickness and the spacerhas a second thickness that is less than the first thickness, andwherein the step of supplying the welding current begins after thewelding base engages the second component and the step of supplying theweld current ends when the spacer comes into contact with both of thecomponents.